documentclass{beamer}
usetheme{Madrid}
title{Beamer columns problem}

begin{document}

frame{titlepage}

begin{frame}{Columns problem}
begin{columns}

column{0.5textwidth}

Column 1 text does not appear unless in itemize environment
or removing titlepage

column{0.4textwidth}

Column 2

end{columns}
end{frame}

begin{frame}{Columns ok}
begin{columns}

column{0.5textwidth}

Column 1

column{0.4textwidth}

Column 2

end{columns}
end{frame}

end{document}